1. Field of the Invention
The present invention relates to a friction material and a braking device and an image forming apparatus using the friction material.
2. Description of the Related Art
Though the present invention is not limited in a subject of application, the following description is made about a case where the present invention is applied to an image forming apparatus represented by a laser printer, a copying machine, or the like, as an example.
Examples of a member equivalent to a rotation body in an image forming apparatus include a carrying roller for carrying a sheet of paper, a photoconductor support member for making a photoconductor run, a charging or transferring roller for applying an electric charge of predetermined polarity to a surface of the aforementioned photoconductor, a fixing roller, or the like.
It is necessary that these rotation bodies are prevented from rotational fluctuations, or the like, caused by disturbance from a driving system such as motors, pulleys, gears, etc. This is because, in the case where prevention of rotational fluctuations, or the like, is not attained, a problem in printing quality is caused so that the image on a recording medium such as a sheet of paper, or the like, may be recorded as an image extended longer or shrunken shorter in the direction of carrying of the recording medium than an image to be recorded originally or so that density irregularity may occur in the recorded image.
In this type image forming apparatus, therefore, a measure is conventionally taken so that a friction material (brake pad) is provided so as to be in contact with a part of the rotation body under a predetermined pressure to thereby prevent the rotational fluctuations, or the like, of the rotation body caused by disturbance from a driving system. The brake pad of polyamide used in the background art was, however, worn out in short time remarkably, so that the brake pad had to be exchanged for a new one frequently.